[PATCH RFC 3/8] SUNRPC: TCP transport support for automated padding of xdr_buf::pages

[Chuck Lever <chuck.lever@oracle.com>]

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/svcsock.c |   39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 2934dd711715..966ea431f845 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -187,14 +187,12 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
 	size_t		base = xdr->page_base;
 	unsigned int	pglen = xdr->page_len;
 	unsigned int	flags = MSG_MORE | MSG_SENDPAGE_NOTLAST;
-	int		slen;
+	int		slen = xdr_buf_msglen(xdr);
 	int		len = 0;
 
-	slen = xdr->len;
-
 	/* send head */
 	if (slen == xdr->head[0].iov_len)
-		flags = 0;
+		flags = MSG_EOR;
 	len = kernel_sendpage(sock, headpage, headoffset,
 				  xdr->head[0].iov_len, flags);
 	if (len != xdr->head[0].iov_len)
@@ -207,7 +205,7 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
 	size = PAGE_SIZE - base < pglen ? PAGE_SIZE - base : pglen;
 	while (pglen > 0) {
 		if (slen == size)
-			flags = 0;
+			flags = MSG_EOR;
 		result = kernel_sendpage(sock, *ppage, base, size, flags);
 		if (result > 0)
 			len += result;
@@ -219,11 +217,21 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
 		base = 0;
 		ppage++;
 	}
+	if (xdr->page_pad) {
+		if (!xdr->tail[0].iov_len)
+			flags = MSG_EOR;
+		result = kernel_sendpage(sock, ZERO_PAGE(0), 0,
+					 xdr->page_pad, flags);
+		if (result > 0)
+			len += result;
+		if (result != xdr->page_pad)
+			goto out;
+	}
 
 	/* send tail */
 	if (xdr->tail[0].iov_len) {
 		result = kernel_sendpage(sock, tailpage, tailoffset,
-				   xdr->tail[0].iov_len, 0);
+					 xdr->tail[0].iov_len, MSG_EOR);
 		if (result > 0)
 			len += result;
 	}
@@ -272,9 +280,9 @@ static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
 			       rqstp->rq_respages[0], tailoff);
 
 out:
-	dprintk("svc: socket %p sendto([%p %zu... ], %d) = %d (addr %s)\n",
+	dprintk("svc: socket %p sendto([%p %zu... ], %zu) = %d (addr %s)\n",
 		svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
-		xdr->len, len, svc_print_addr(rqstp, buf, sizeof(buf)));
+		xdr_buf_msglen(xdr), len, svc_print_addr(rqstp, buf, sizeof(buf)));
 
 	return len;
 }
@@ -1134,24 +1142,25 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
 static int svc_tcp_sendto(struct svc_rqst *rqstp)
 {
 	struct xdr_buf	*xbufp = &rqstp->rq_res;
+	u32 reclen = xdr_buf_msglen(xbufp);
+	__be32 marker;
 	int sent;
-	__be32 reclen;
 
 	/* Set up the first element of the reply kvec.
 	 * Any other kvecs that may be in use have been taken
 	 * care of by the server implementation itself.
 	 */
-	reclen = htonl(0x80000000|((xbufp->len ) - 4));
-	memcpy(xbufp->head[0].iov_base, &reclen, 4);
+	marker = cpu_to_be32(0x80000000 | (reclen - sizeof(marker)));
+	memcpy(xbufp->head[0].iov_base, &marker, sizeof(marker));
 
 	sent = svc_sendto(rqstp, &rqstp->rq_res);
-	if (sent != xbufp->len) {
+	if (sent != reclen) {
 		printk(KERN_NOTICE
-		       "rpc-srv/tcp: %s: %s %d when sending %d bytes "
+		       "rpc-srv/tcp: %s: %s %d when sending %u bytes "
 		       "- shutting down socket\n",
 		       rqstp->rq_xprt->xpt_server->sv_name,
-		       (sent<0)?"got error":"sent only",
-		       sent, xbufp->len);
+		       (sent<0)?"got error":"sent",
+		       sent, reclen);
 		set_bit(XPT_CLOSE, &rqstp->rq_xprt->xpt_flags);
 		svc_xprt_enqueue(rqstp->rq_xprt);
 		sent = -EAGAIN;